lib/float/index.js
"use strict";
module.exports = factory(factory);
/**
* Reads / writes floats / doubles from / to buffers.
* @name util.float
* @namespace
*/
/**
* Writes a 32 bit float to a buffer using little endian byte order.
* @name util.float.writeFloatLE
* @function
* @param {number} val Value to write
* @param {Uint8Array} buf Target buffer
* @param {number} pos Target buffer offset
* @returns {undefined}
*/
/**
* Writes a 32 bit float to a buffer using big endian byte order.
* @name util.float.writeFloatBE
* @function
* @param {number} val Value to write
* @param {Uint8Array} buf Target buffer
* @param {number} pos Target buffer offset
* @returns {undefined}
*/
/**
* Reads a 32 bit float from a buffer using little endian byte order.
* @name util.float.readFloatLE
* @function
* @param {Uint8Array} buf Source buffer
* @param {number} pos Source buffer offset
* @returns {number} Value read
*/
/**
* Reads a 32 bit float from a buffer using big endian byte order.
* @name util.float.readFloatBE
* @function
* @param {Uint8Array} buf Source buffer
* @param {number} pos Source buffer offset
* @returns {number} Value read
*/
/**
* Writes a 64 bit double to a buffer using little endian byte order.
* @name util.float.writeDoubleLE
* @function
* @param {number} val Value to write
* @param {Uint8Array} buf Target buffer
* @param {number} pos Target buffer offset
* @returns {undefined}
*/
/**
* Writes a 64 bit double to a buffer using big endian byte order.
* @name util.float.writeDoubleBE
* @function
* @param {number} val Value to write
* @param {Uint8Array} buf Target buffer
* @param {number} pos Target buffer offset
* @returns {undefined}
*/
/**
* Reads a 64 bit double from a buffer using little endian byte order.
* @name util.float.readDoubleLE
* @function
* @param {Uint8Array} buf Source buffer
* @param {number} pos Source buffer offset
* @returns {number} Value read
*/
/**
* Reads a 64 bit double from a buffer using big endian byte order.
* @name util.float.readDoubleBE
* @function
* @param {Uint8Array} buf Source buffer
* @param {number} pos Source buffer offset
* @returns {number} Value read
*/
// Factory function for the purpose of node-based testing in modified global environments
function factory(exports) {
// float: typed array
if (typeof Float32Array !== "undefined") (function() {
var f32 = new Float32Array([ -0 ]),
f8b = new Uint8Array(f32.buffer),
le = f8b[3] === 128;
function writeFloat_f32_cpy(val, buf, pos) {
f32[0] = val;
buf[pos ] = f8b[0];
buf[pos + 1] = f8b[1];
buf[pos + 2] = f8b[2];
buf[pos + 3] = f8b[3];
}
function writeFloat_f32_rev(val, buf, pos) {
f32[0] = val;
buf[pos ] = f8b[3];
buf[pos + 1] = f8b[2];
buf[pos + 2] = f8b[1];
buf[pos + 3] = f8b[0];
}
/* istanbul ignore next */
exports.writeFloatLE = le ? writeFloat_f32_cpy : writeFloat_f32_rev;
/* istanbul ignore next */
exports.writeFloatBE = le ? writeFloat_f32_rev : writeFloat_f32_cpy;
function readFloat_f32_cpy(buf, pos) {
f8b[0] = buf[pos ];
f8b[1] = buf[pos + 1];
f8b[2] = buf[pos + 2];
f8b[3] = buf[pos + 3];
return f32[0];
}
function readFloat_f32_rev(buf, pos) {
f8b[3] = buf[pos ];
f8b[2] = buf[pos + 1];
f8b[1] = buf[pos + 2];
f8b[0] = buf[pos + 3];
return f32[0];
}
/* istanbul ignore next */
exports.readFloatLE = le ? readFloat_f32_cpy : readFloat_f32_rev;
/* istanbul ignore next */
exports.readFloatBE = le ? readFloat_f32_rev : readFloat_f32_cpy;
// float: ieee754
})(); else (function() {
function writeFloat_ieee754(writeUint, val, buf, pos) {
var sign = val < 0 ? 1 : 0;
if (sign)
val = -val;
if (val === 0)
writeUint(1 / val > 0 ? /* positive */ 0 : /* negative 0 */ 2147483648, buf, pos);
else if (isNaN(val))
writeUint(2143289344, buf, pos);
else if (val > 3.4028234663852886e+38) // +-Infinity
writeUint((sign << 31 | 2139095040) >>> 0, buf, pos);
else if (val < 1.1754943508222875e-38) // denormal
writeUint((sign << 31 | Math.round(val / 1.401298464324817e-45)) >>> 0, buf, pos);
else {
var exponent = Math.floor(Math.log(val) / Math.LN2),
mantissa = Math.round(val * Math.pow(2, -exponent) * 8388608) & 8388607;
writeUint((sign << 31 | exponent + 127 << 23 | mantissa) >>> 0, buf, pos);
}
}
exports.writeFloatLE = writeFloat_ieee754.bind(null, writeUintLE);
exports.writeFloatBE = writeFloat_ieee754.bind(null, writeUintBE);
function readFloat_ieee754(readUint, buf, pos) {
var uint = readUint(buf, pos),
sign = (uint >> 31) * 2 + 1,
exponent = uint >>> 23 & 255,
mantissa = uint & 8388607;
return exponent === 255
? mantissa
? NaN
: sign * Infinity
: exponent === 0 // denormal
? sign * 1.401298464324817e-45 * mantissa
: sign * Math.pow(2, exponent - 150) * (mantissa + 8388608);
}
exports.readFloatLE = readFloat_ieee754.bind(null, readUintLE);
exports.readFloatBE = readFloat_ieee754.bind(null, readUintBE);
})();
// double: typed array
if (typeof Float64Array !== "undefined") (function() {
var f64 = new Float64Array([-0]),
f8b = new Uint8Array(f64.buffer),
le = f8b[7] === 128;
function writeDouble_f64_cpy(val, buf, pos) {
f64[0] = val;
buf[pos ] = f8b[0];
buf[pos + 1] = f8b[1];
buf[pos + 2] = f8b[2];
buf[pos + 3] = f8b[3];
buf[pos + 4] = f8b[4];
buf[pos + 5] = f8b[5];
buf[pos + 6] = f8b[6];
buf[pos + 7] = f8b[7];
}
function writeDouble_f64_rev(val, buf, pos) {
f64[0] = val;
buf[pos ] = f8b[7];
buf[pos + 1] = f8b[6];
buf[pos + 2] = f8b[5];
buf[pos + 3] = f8b[4];
buf[pos + 4] = f8b[3];
buf[pos + 5] = f8b[2];
buf[pos + 6] = f8b[1];
buf[pos + 7] = f8b[0];
}
/* istanbul ignore next */
exports.writeDoubleLE = le ? writeDouble_f64_cpy : writeDouble_f64_rev;
/* istanbul ignore next */
exports.writeDoubleBE = le ? writeDouble_f64_rev : writeDouble_f64_cpy;
function readDouble_f64_cpy(buf, pos) {
f8b[0] = buf[pos ];
f8b[1] = buf[pos + 1];
f8b[2] = buf[pos + 2];
f8b[3] = buf[pos + 3];
f8b[4] = buf[pos + 4];
f8b[5] = buf[pos + 5];
f8b[6] = buf[pos + 6];
f8b[7] = buf[pos + 7];
return f64[0];
}
function readDouble_f64_rev(buf, pos) {
f8b[7] = buf[pos ];
f8b[6] = buf[pos + 1];
f8b[5] = buf[pos + 2];
f8b[4] = buf[pos + 3];
f8b[3] = buf[pos + 4];
f8b[2] = buf[pos + 5];
f8b[1] = buf[pos + 6];
f8b[0] = buf[pos + 7];
return f64[0];
}
/* istanbul ignore next */
exports.readDoubleLE = le ? readDouble_f64_cpy : readDouble_f64_rev;
/* istanbul ignore next */
exports.readDoubleBE = le ? readDouble_f64_rev : readDouble_f64_cpy;
// double: ieee754
})(); else (function() {
function writeDouble_ieee754(writeUint, off0, off1, val, buf, pos) {
var sign = val < 0 ? 1 : 0;
if (sign)
val = -val;
if (val === 0) {
writeUint(0, buf, pos + off0);
writeUint(1 / val > 0 ? /* positive */ 0 : /* negative 0 */ 2147483648, buf, pos + off1);
} else if (isNaN(val)) {
writeUint(0, buf, pos + off0);
writeUint(2146959360, buf, pos + off1);
} else if (val > 1.7976931348623157e+308) { // +-Infinity
writeUint(0, buf, pos + off0);
writeUint((sign << 31 | 2146435072) >>> 0, buf, pos + off1);
} else {
var mantissa;
if (val < 2.2250738585072014e-308) { // denormal
mantissa = val / 5e-324;
writeUint(mantissa >>> 0, buf, pos + off0);
writeUint((sign << 31 | mantissa / 4294967296) >>> 0, buf, pos + off1);
} else {
var exponent = Math.floor(Math.log(val) / Math.LN2);
if (exponent === 1024)
exponent = 1023;
mantissa = val * Math.pow(2, -exponent);
writeUint(mantissa * 4503599627370496 >>> 0, buf, pos + off0);
writeUint((sign << 31 | exponent + 1023 << 20 | mantissa * 1048576 & 1048575) >>> 0, buf, pos + off1);
}
}
}
exports.writeDoubleLE = writeDouble_ieee754.bind(null, writeUintLE, 0, 4);
exports.writeDoubleBE = writeDouble_ieee754.bind(null, writeUintBE, 4, 0);
function readDouble_ieee754(readUint, off0, off1, buf, pos) {
var lo = readUint(buf, pos + off0),
hi = readUint(buf, pos + off1);
var sign = (hi >> 31) * 2 + 1,
exponent = hi >>> 20 & 2047,
mantissa = 4294967296 * (hi & 1048575) + lo;
return exponent === 2047
? mantissa
? NaN
: sign * Infinity
: exponent === 0 // denormal
? sign * 5e-324 * mantissa
: sign * Math.pow(2, exponent - 1075) * (mantissa + 4503599627370496);
}
exports.readDoubleLE = readDouble_ieee754.bind(null, readUintLE, 0, 4);
exports.readDoubleBE = readDouble_ieee754.bind(null, readUintBE, 4, 0);
})();
return exports;
}
// uint helpers
function writeUintLE(val, buf, pos) {
buf[pos ] = val & 255;
buf[pos + 1] = val >>> 8 & 255;
buf[pos + 2] = val >>> 16 & 255;
buf[pos + 3] = val >>> 24;
}
function writeUintBE(val, buf, pos) {
buf[pos ] = val >>> 24;
buf[pos + 1] = val >>> 16 & 255;
buf[pos + 2] = val >>> 8 & 255;
buf[pos + 3] = val & 255;
}
function readUintLE(buf, pos) {
return (buf[pos ]
| buf[pos + 1] << 8
| buf[pos + 2] << 16
| buf[pos + 3] << 24) >>> 0;
}
function readUintBE(buf, pos) {
return (buf[pos ] << 24
| buf[pos + 1] << 16
| buf[pos + 2] << 8
| buf[pos + 3]) >>> 0;
}